Initialize section in Flash Memory

Hi Pierre,

fo this case I would not edit the linker command file; I recommend changeing your code as follows:

// assign the variable into data section

#pragma DATA_SECTION(cFlashPsmId, ".infoB"); // you did this in your example

// allocate appropriate size in bytes (one byte) for the variable

#pragma DATA_ALIGN(cFlashPsmId, 1); // this one needs to be added

// declare the variable

const char cFlashPsmId;

Refer to slau131c.pdf (Chapter 7) for details on the above!!
aBUGSworstnightmare

Thanks for your reply.

Unfortunaly it does not seem to work as I wish.

http://img242.imageshack.us/img242/354/croppercapture8.png

Did I do someting wrong ?

Hi Pierre_,

be shure to ckeck your FET Debugger settings; by default code and info memory will be erased when you download your application!

Have a look at PROJECT-->FET DEBUGGER-->DOWNLOAD and select the option ERASE MAIN MEMORY to prevent erasing of your info memory. Now it should work.

Rgds
aBUGSworstnightmare

 Thanks for your help, but...

It does not.

Anyway , according to SLA132C , the only thing that DATA_ALIGN Pragma directive do is to  align symbol in memory. (Not to allocate space).

And Info Memory should (/must) be erased first before writing any data.

I'm not sure we are on the way. (..to solve the problem)

In 5.11.2 of SLAU132C

"You can use the DATA_SECTION pragma to put the variable in a section other than .const. For example,
the following C code:
#pragma DATA_SECTION (var, ".mysect");
const int zero=0;
is compiled into this assembly code:
.sect .mysect
_zero
.word 0"

OK That's what I need..

The C Code:

#pragma DATA_SECTION (cFlashPsmId,".infoB")
const char cFlashPsmId=6;

produces assembly output :

.global cFlashPsmId
.sect ".infoB"
.align 1
cFlashPsmId:
.field 6,8 ; cFlashPsmId @ 0

But *HOW* to prevent the compiler to  treat cFlashPsmId as a constant

For example

C code

idx=cFlashPsmId-1;

produces

MOV.B #0x0005,R12

Hi,

if you declare a variable as a constant you will ge a constant (placed in your own memory segment (INFOB in your case))! Pls review my post above.

INFOB is a Flash Memory and NOT EEPROM --> if you want to write new data to it you will have to erase it first (and than write your data). Have a look at the forum; there are various posts with C-Sample for writing to Flash/INFOx memory.

Rgds
aBUGSworstnightmare

thanks but I have no problem with writing in Flash Memory.

(It seems that we do not understand each other.)

 The only thing I wish is to Initialize data in specific section that lies in flash memory (out of .const sections)

Hi,

if you think that this is the best option for you it's o.k. (but it wouldn't be the best one for me ..)

aBUGSworstnightmare

Pierre,

I have an aternate suggestion that I usuallly use.  I store al my settings in flash.

The way that I d it is I create a structure with al my settings and initialization constants.. when the program boots it sequentialy copies the data byte by byte into the structure.. I then check the structure and see if it has valid data (I us a magic number for each version) if not, I set the defauts in the structure (for a specific version) and then copy this data to flash, I can also use this for upgrades...  now I can freely modify the variables in the strutre as needed, if I make a change that I want to say I just copy the structure back to flash.. I dont have to worry about any special pragmas or how the compiler wil handle things since I am operating on a r/w structure that I can load or save whenever I want..